Manufacture of refined oils



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- ".EST 3. COBB, OE JERSEY CITY, NEW JERSEY, ASSIGNOR T STANDARDDEVELOP- KENT COMBANY, A CORPORATION OF DELAWARE.

' MANUF ACTURE ornnrmnn OILS.

No Drawing. Original application filed April 8, 1922. Serial No.550,865. Divided and this application filed February 24, 1926. SerialNo. 90,415.

The present invention relates to the manufacture of refined oils andmore particularly of refined viscous oils such as lubricating oils,water white or medicinal oils and the like.

In the refining of such oils, the stock,

which is in general a distillate or cut obtained from crude oil afterthe kerosene or burning oil out haszbeen removed, is subjected to anacid treatment with strong sulfuric acid, for example, with 66 B6. acidorfuming acid. The treatment with sulfuric acid may be heavy or. light;that is, with greater or less amounts of acid, in accordance with theextent to which the refining of the oil is to be carried. The action ofthe acid upon the hydrocarbons of the oil appears to form, among othercompounds, sulfo-compounds, which are in part dissolved in the sludgewhich is settled out of the oil, and are in part retained in the oil. vThe proportion and the specific characteristics of thesulfo-compoundsretained in the oil: vary to some extent with the character of oiltreated and with thenature of the treatment. Thus, in a light acidtreatment with 66 B. acid for the production of lubricating oils, a lessproportion of these compounds appears to be formed than in the heavyacid treatments with fuming acid employed in the case of the manufactureof white oils or medicinal oils. The character of the oil appears toinfluence to a marked degree the ease of removal of the retainedsulfo-compounds.

In accordance with the present invention, the oil to be refined issubjected to the desired acid treatment which may be with 66 acid orfuming acid and in one or a plurality of dumps. The sludge is-removedfrom the treated. oil as completely as possible by set-s: tling, and, ifequipment permits, it is desirable that this settling he continued fortwo or three days or even longer.

After the last acid treatment and removal of acid sludge, the oil isneutralized, for 7 example with caustic soda solution. Thisneutralization is an important step in the process; it serves to fix thesulfo-compounds, rendering them involatile when the oil is distilled.This distillation is preferably made with fire and steam to a 5 to 10%bottom. The alkali sludge is removed before the oil is distilled. .Thedistilled oil is then given a light treatment with fuming sulfuric acidand allowed to settle. The sludge is removed and the sour oil is thenheated to a temperature between 350 and 500 F.,

and preferably at about 380 F. In order to carry off the volatileproducts formed, it is found desirable to pass steam through the oilduring the heat treatment, the steam be-v ing also effective inagitating the oil to cause uniform heating thereof and in removing anyyolatile oil or gas present, which is not desired in the final product.During the heat treatment acidity of the oil decreases and-it becomessubstantially neutral and will not tarnish copper at the end of thetreatment.

The heating is continued for a period sufficient to place the oil in thecondition just described. This period will vary, but for most purposesit will be fifteen hours or longer. A heating period of twenty hours isoften found best. During the heating, the elementary sulfur, sulfurcombinations and unstable compounds combine or decompose, with theformation of some volatile and some non-volatile and otherwise morestable products.

As mentioned above, the steam serves to carry off the volatile productsformed.

The removal of non-volatile products of decomposition of thesulfo-compounds and other undesirable bodies caused by the heattreatment from the oil, if they are not excessively large in amount, maybe effected by filtration of the oil through fullers earth or Floridaclay. When the propor-. tion of decomposition products formed is solarge, or they are of such character that filtration through Floridaclay alone is not wholly'efiective or is uneconomical, the colloidalproducts of decomposition may be in whole or in part 'coagulated andremoved by washing with acid, preferably sulfuric acid of 66 B. orweaker. After this washing, the oil having been thoroughly settled.

p A suitable its refining may be completed by direct filtration throughfullers earth.

The following examples illustrate the practice of the present invention:

Example N o. 1.

In preparing a medicinal oil from West Columbia or Coastal stock, whichappears to contain both naphthenic and asphaltic compounds, a suitabledistillate is selected, for example one having a viscosity of 450seconds Saybolt at 100 F., a gravity of about 22 B. and a flash point of370 F. This stock is treated with fuming sulfuric acid containing 20%anhydride, a suitable proportion being 37% by volume. The treatment ispreferably effected in five dumps of approximately equal proportions.After each dump the oil is settled, suitably from twenty-four toforty-eight hours, and the sludge removed. Before each dump the oil ispreferably cooled to below 70 F. After the last treatment, the slud e isdrawn off and the batch is neutralized, for example, with 12 B. causticsoda solution. The alkali sludge is removed and the oil may then, ifdesired, be blown with air at about 180 to 200 F. This air blowingremoves water. After neutralization the oil is distilled with fire andsteam to a bottom of to the distillate being collected as a whole, withthe exception of the light constituents which might undesirably reducethe flash point of the product. This distillation, as described in myPatent'No. 1,388,- 517, granted August 23, 1921, leaves thesulfo-compounds inthe form of their sodium salts or soaps in theresidue, the distillate being substantially free therefrom. 1 I

The distillate may be chilled or pressed t remove wax, if desired, andis treated again with a small proportion of the fuming acid.

roportion is by volume, the treatment being preferably carried out intwo dumps of approximately equal proportions. After this acid treatmentthe oil is allowed to settle for as long a period as possible, two orthree days at least. The sour oil is then subjected to the heattreatment above described, being heated preferably to 380 to 410 F. forabout twenty hours, with the injection of steam to effectthe removal ofvolatile decomposition products and sulphur dioxide. At the end of theheat treatment the oil is cooled and filtered through fullers earth, thepreliminary coagulation of suspended matter with acid as described abovebeing desirable but not usually necessary in this case. The finished oilhas a viscosity of 200 to 210 seconds Saybolt at 100 and a gravity ofabout 29 B.

Example No. 2. A distillate from a Coastal crude, having a gravity of223 Be, a flash point of 325 F., a viscosity of 125 seconds Saybolt at100 F., and a zero cold test, is treated for the production of a whitemedicinal oil in the manner described in Example No. 1 above, exceptthat the pressing of the distillate from the oil after the first acidtreatment is unnecessary and the heat treatment or steaming of the oilafter the second acid treatment is carried out at about 380 F.

Although the present invention has been 0 described in connection withthe details of specific methods for carrying it into effect, it is notintended that these shall be regarded as limitations upon the scope ofthe invention, except in so far as retained in the accompanying claims.

The present application is a division ofmy copending application SerialNo. 550,-.

865, filed April 8, 1922.

I claim:

1. The process of refining heavy distillates, which comprises treatingsuch distillates with a large amount of fuming sulfuric acid,neutralizing the acid treated oil, distilling the oil with fire andsteam to a 5 to 10% bottom, collecting the distillate, retreatingv thedistillate with a less proportion of fuming sulfuric acid, heating theresulting sour oil to about 3505 00 F. while passing steam therethrough,continuing the heating and steaming until the oil becomes substantiallyneutral and will not tarnish copper, and filtering the oil.

2. The process according to claim 1, in which the fire and steamdistillate is treated for the removal of wax before the second acidtreatment.

3. The process according to claim 1, in which the distillate is selectedfrom stocks of the type of West Columbia or Coastal oil, said distillatehaving a viscosity of about 4.50 seconds Saybolt at F. and a gravity ofabout 22 B.

4. The process of refining heavy distillates, which comprises subjectingsuch distillates to heavy acid treatment with fumim sulfuric acid,ucutralizing the acid treated oil, distilling the oil with fire andsteam to a 5 to 10% bottom, collecting the distillate, re treating thedistillate with a less proportion of fuming sulfuric acid, heating theresultingsour oil to about 380 F. for eighteen to twenty hours whilepassing steam therethrough, and filtering the oil.

5. The process of refining heavy distil- 139 lates, which comprisessubjecting such distilletes to heavy acid treatment with fuming sulfuricacid in a plurality of stages, removing the sludge formed after eachacid treatment, neutralizing the 'oil, removing the constituents,removing wax from the distil- 1 late, then treating the distillate witha small proportion of fuming acid; removing sludge,

sub ecting the residual sour oil to. heat treatment at about 380 to 410F. for about twenty hours with the injection of steam, 1 and cooling andfiltering the oil.

ERNEST B. COBB.

